/// <summary>
/// Applies the Namespace Attributes of an Element Event to the Namespace Map
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="evt">Element Event</param>
private void ApplyNamespaces(RdfXmlParserContext context, ElementEvent evt)
{
if (!evt.BaseUri.Equals(String.Empty))
{
Uri baseUri = UriFactory.Create(Tools.ResolveUri(evt.BaseUri, context.BaseUri.ToSafeString()));
context.BaseUri = baseUri;
if (!context.Handler.HandleBaseUri(baseUri)) ParserHelper.Stop();
}
foreach (NamespaceAttributeEvent ns in evt.NamespaceAttributes)
{
if (!context.Namespaces.HasNamespace(ns.Prefix) || !context.Namespaces.GetNamespaceUri(ns.Prefix).ToString().Equals(ns.Uri))
{
context.Namespaces.AddNamespace(ns.Prefix, UriFactory.Create(ns.Uri));
if (!context.Handler.HandleNamespace(ns.Prefix, UriFactory.Create(ns.Uri))) ParserHelper.Stop();
}
}
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'RDF'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="element">RDF Element to apply Production to</param>
private void GrammarProductionRDF(RdfXmlParserContext context, ElementEvent element)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTrace("RDF");
}
//Check Uri is correct (using the QName for simplicity)
if (!element.QName.Equals("rdf:RDF") && !element.QName.Equals(":RDF"))
{
throw ParserHelper.Error("Unexpected Node '" + element.QName + "', an 'rdf:RDF' node was expected", "RDF", element);
}
//Check has no Attributes
if (element.Attributes.Count > 0)
{
throw ParserHelper.Error("Root Node should not contain any attributes other than XML Namespace Declarations", "RDF", element);
}
//Apply Namespaces
this.ApplyNamespaces(context, element);
//Build a Sublist of all Nodes up to the matching EndElement
IEventQueue subevents = new EventQueue();
IRdfXmlEvent next;
//Make sure we discard the current ElementEvent which will be at the front of the queue
context.Events.Dequeue();
//Gather the Sublist
while (context.Events.Count > 1)
{
subevents.Enqueue(context.Events.Dequeue());
}
//Call the NodeElementList Grammer Production
this.GrammarProductionNodeElementList(context, subevents);
//Next Event in queue should be an EndElementEvent or we Error
next = context.Events.Dequeue();
if (!(next is EndElementEvent))
{
throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', an EndElementEvent was expected", "RDF", element);
}
}
/// <summary>
/// Reads RDF/XML syntax from some Input using a RDF Handler
/// </summary>
/// <param name="handler">RDF Handler to use</param>
/// <param name="input">Input to read from</param>
public void Load(IRdfHandler handler, TextReader input)
{
if (handler == null) throw new RdfParseException("Cannot read RDF into a null RDF Handler");
if (input == null) throw new RdfParseException("Cannot read RDF from a null TextReader");
try
{
//Silverlight only supports XmlReader not the full XmlDocument API
#if !NO_XMLDOM
if (this._mode == RdfXmlParserMode.DOM)
{
//Load XML from Stream
XmlDocument doc = new XmlDocument();
doc.Load(input);
//Create a new Parser Context and Parse
RdfXmlParserContext context = new RdfXmlParserContext(handler, doc, this._traceparsing);
this.Parse(context);
}
else
{
#endif
RdfXmlParserContext context = new RdfXmlParserContext(handler, input);
this.Parse(context);
#if !NO_XMLDOM
}
#endif
}
catch (XmlException xmlEx)
{
//Wrap in a RDF Parse Exception
throw new RdfParseException("Unable to Parse this RDF/XML since System.Xml was unable to parse the document, see Inner Exception for details", new PositionInfo(xmlEx.LineNumber, xmlEx.LinePosition), xmlEx);
}
catch (IOException ioEx)
{
//Wrap in a RDF Parse Exception
throw new RdfParseException("Unable to Parse this RDF/XML due to an IO Exception, see Inner Exception for details", ioEx);
}
catch (Exception)
{
//Throw unexpected errors upwards as-is
throw;
}
finally
{
try
{
input.Close();
}
catch
{
//Ignore exceptions here - just trying to clean up properly
}
}
}
/// <summary>
/// Given an XML Node that is the Root of the RDF/XML section of the Document Tree creates the RootEvent and generates the rest of the Event Tree by recursive calls to the <see cref="GenerateEvents">GenerateEvents</see> method
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="docEl">XML Node that is the Root of the RDF/XML section of the Document Tree</param>
/// <returns></returns>
private RootEvent GenerateEventTree(RdfXmlParserContext context, XmlNode docEl)
{
//Get the Document Element
//XmlNode docEl = document.DocumentElement;
//Generate a Root Event and Element Event from it
RootEvent root = new RootEvent(docEl.BaseURI, docEl.OuterXml);
if (docEl.BaseURI.Equals(String.Empty))
{
if (context.BaseUri != null)
{
root.BaseUri = context.BaseUri.ToString();
}
}
ElementEvent element = new ElementEvent(docEl.LocalName, docEl.Prefix, root.BaseUri, docEl.OuterXml);
//Initialise Language Settings
root.Language = String.Empty;
element.Language = root.Language;
//Set as Document Element and add as only Child
root.DocumentElement = element;
root.Children.Add(element);
#region Attribute Processing
//Go through attributes looking for XML Namespace Declarations
foreach (XmlAttribute attr in docEl.Attributes)
{
if (attr.Prefix.Equals("xmlns") || attr.Name == "xmlns")
{
//Define a Namespace
String prefix = attr.LocalName;
if (prefix.Equals("xmlns")) prefix = String.Empty;
String uri;
if (attr.Value.StartsWith("http://"))
{
//Absolute Uri
uri = attr.Value;
}
else if (!root.BaseUri.Equals(String.Empty))
{
//Relative Uri with a Base Uri to resolve against
//uri = root.BaseUri + attr.Value;
uri = Tools.ResolveUri(attr.Value, root.BaseUri);
}
else
{
//Relative Uri with no Base Uri
throw new RdfParseException("Cannot resolve a Relative Namespace URI since there is no in-scope Base URI");
}
context.Namespaces.AddNamespace(prefix, new Uri(uri));
}
else if (attr.Name == "xml:base")
{
//Set the Base Uri
String baseUri = attr.Value;
if (RdfXmlSpecsHelper.IsAbsoluteURI(baseUri))
{
//Absolute Uri
root.BaseUri = baseUri;
}
else if (!element.BaseUri.Equals(String.Empty))
{
//Relative Uri with a Base Uri to resolve against
//root.BaseUri += baseUri;
root.BaseUri = Tools.ResolveUri(baseUri, root.BaseUri);
}
else
{
//Relative Uri with no Base Uri
throw new RdfParseException("Cannot resolve a Relative Base URI since there is no in-scope Base URI");
}
element.BaseUri = root.BaseUri;
}
}
#endregion
//Iterate over Children
foreach (XmlNode child in docEl.ChildNodes)
{
//Ignore Irrelevant Node Types
if (this.IsIgnorableNode(child))
{
continue;
}
//Generate an Event for the Child Node
ElementEvent childEvent = this.GenerateEvents(context, child, element);
element.Children.Add(childEvent);
}
//Return the Root Event
return root;
}
/// <summary>
/// Takes the Event Tree and Flattens it into a Queue as per the rules laid out in the RDF/XML Specification
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="evt">Event which is the Root of the Tree (not necessarily a RootEvent)</param>
/// <param name="nesting">A numeric value used for Parser Tracing to indicate nesting levels of the Event Tree</param>
private void FlattenEventTree(RdfXmlParserContext context, IRdfXmlEvent evt, int nesting)
{
//Add to Queue
context.Events.Enqueue(evt);
if (context.TraceParsing)
{
Console.Write(nesting + " " + evt.GetType().ToString());
}
//Iterate over Children where present
if (evt is RootEvent)
{
RootEvent root = (RootEvent)evt;
if (context.TraceParsing)
{
Console.WriteLine("");
}
foreach (IRdfXmlEvent childEvent in root.Children)
{
this.FlattenEventTree(context, childEvent, nesting + 1);
}
//No End after a RootEvent
return;
}
else if (evt is ElementEvent)
{
ElementEvent element = (ElementEvent)evt;
if (context.TraceParsing)
{
Console.WriteLine(" " + element.Namespace + ":" + element.LocalName);
}
if (element.Children.Count > 0)
{
foreach (IRdfXmlEvent childEvent in element.Children)
{
this.FlattenEventTree(context, childEvent, nesting + 1);
}
}
}
else if (evt is TextEvent)
{
TextEvent text = (TextEvent)evt;
if (context.TraceParsing)
{
Console.WriteLine(" " + text.Value);
}
//No additional End after a Text Event
return;
}
else if (evt is TypedLiteralEvent)
{
TypedLiteralEvent tlit = (TypedLiteralEvent)evt;
if (context.TraceParsing)
{
Console.WriteLine();
}
//No additional End after a Text Event
return;
}
//Add an End Element Event to the Queue
EndElementEvent end = new EndElementEvent();
context.Events.Enqueue(end);
if (context.TraceParsing)
{
String endDescrip = String.Empty;
if (evt is ElementEvent)
{
ElementEvent temp = (ElementEvent)evt;
endDescrip = " " + temp.QName;
}
Console.WriteLine(nesting + " " + end.GetType().ToString() + endDescrip);
}
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'literalPropertyElt'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="eventlist">Queue of Events that make up the Literal Property Element and its Children</param>
/// <param name="parent">Parent Event (ie. Node) of the Property Element</param>
private void GrammarProductionLiteralPropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTracePartial("Literal Property Element");
}
//Get the 3 Events (should only be three)
IRdfXmlEvent first, middle, last;
first = eventlist.Dequeue();
middle = eventlist.Dequeue();
last = eventlist.Dequeue();
//If Queue is non-empty then Error
if (eventlist.Count > 0)
{
throw ParserHelper.Error("Too many events encountered while trying to parse a Literal Property Element", first);
}
ElementEvent element = (ElementEvent)first;
if (this._traceparsing) this.ProductionTracePartial(element);
//Apply Namespaces
this.ApplyNamespaces(context, element);
//Validate that the middle event is a TextEvent
if (!(middle is TextEvent))
{
throw ParserHelper.Error("Unexpected event '" + middle.GetType().ToString() + "', expected a TextEvent in a Literal Property Element", middle);
}
TextEvent text = (TextEvent)middle;
//Validate the Attributes
String ID = String.Empty;
String datatype = String.Empty;
if (element.Attributes.Count > 2)
{
throw ParserHelper.Error("A Literal Property Element contains too many attributes, only rdf:ID and rdf:datatype are permitted", element);
}
else
{
//Only rdf:ID and rdf:datatype allowed
foreach (AttributeEvent a in element.Attributes)
{
if (RdfXmlSpecsHelper.IsIDAttribute(a)) {
ID = "#" + a.Value;
}
else if (RdfXmlSpecsHelper.IsDataTypeAttribute(a))
{
datatype = a.Value;
}
else
{
throw ParserHelper.Error("A Literal Property Element contains an unexpected attribute, only rdf:ID and rdf:datatype are permitted", element);
}
}
}
//Create the Nodes for the Graph
INode subj, pred, obj;
//Get the Subject from the Parent
ElementEvent parentEl = (ElementEvent)parent;
subj = parentEl.SubjectNode;
//Validate the ID (if any)
if (!ID.Equals(String.Empty))
{
this.ValidateID(context, ID.Substring(1), subj);
}
//Create a Predicate from this Element
pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName);
//Create an Object from the Text Event
if (datatype.Equals(String.Empty))
{
//No Type with possible Language
if (element.Language.Equals(String.Empty))
{
obj = context.Handler.CreateLiteralNode(text.Value);
}
else
{
obj = context.Handler.CreateLiteralNode(text.Value, element.Language);
}
}
else
{
//Typed
//Resolve the Datatype Uri
UriReferenceEvent dtref = new UriReferenceEvent(datatype, String.Empty);
IUriNode dturi = this.Resolve(context, dtref, element.BaseUri);
obj = context.Handler.CreateLiteralNode(text.Value, dturi.Uri);
}
//Assert the Triple
if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop();
//Reify if applicable
if (!ID.Equals(String.Empty))
{
//Resolve the Uri
UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty);
IUriNode uri = this.Resolve(context, uriref,element.BaseUri);
this.Reify(context, uri, subj, pred, obj);
}
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'nodeElementList'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="eventlist">Queue of Events to apply the Production to</param>
private void GrammarProductionNodeElementList(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTrace("Node Element List");
}
IRdfXmlEvent next;
//Want to break up into a number of sublists
while (eventlist.Count > 0)
{
//Create a new Sublist
IEventQueue<IRdfXmlEvent> subevents = new EventQueue<IRdfXmlEvent>();
int nesting = 0;
//Gather the Sublist taking account of nesting
do
{
next = eventlist.Dequeue();
subevents.Enqueue(next);
if (next is ElementEvent)
{
nesting++;
}
else if (next is EndElementEvent)
{
nesting--;
}
} while (nesting > 0);
//Call the next Grammar Production
this.GrammarProductionNodeElement(context, subevents);
}
}
/// <summary>
/// Function which does the actual Parsing by invoking the various steps of the Parser
/// </summary>
/// <param name="context">Parser Context</param>
private void Parse(RdfXmlParserContext context)
{
try
{
context.Handler.StartRdf();
//Trace Parser Information
if (this._traceparsing)
{
Console.WriteLine("Trace Format is as follows:");
Console.WriteLine("NestingLevel EventType [Description]");
Console.WriteLine();
}
//Process the Queue
this.ProcessEventQueue(context);
context.Handler.EndRdf(true);
}
catch (RdfParsingTerminatedException)
{
context.Handler.EndRdf(true);
//Discard this - it justs means the Handler told us to stop
}
catch
{
context.Handler.EndRdf(false);
throw;
}
}
/// <summary>
/// Starts the Parsing of the flattened Event Tree by calling the appropriate Grammar Production based on the type of the First Event in the Queue
/// </summary>
private void ProcessEventQueue(RdfXmlParserContext context)
{
//Get First Event
IRdfXmlEvent first = context.Events.Dequeue();
bool setBaseUri = (context.BaseUri == null);
Uri baseUri;
if (first is RootEvent)
{
this.GrammarProductionDoc(context, (RootEvent)first);
if (setBaseUri && !((RootEvent)first).BaseUri.Equals(String.Empty))
{
baseUri = UriFactory.Create(Tools.ResolveUri(((RootEvent)first).BaseUri, String.Empty));
context.BaseUri = baseUri;
if (!context.Handler.HandleBaseUri(baseUri)) ParserHelper.Stop();
}
}
else
{
this.GrammarProductionRDF(context, (ElementEvent)first);
if (setBaseUri && !((ElementEvent)first).BaseUri.Equals(String.Empty))
{
baseUri = UriFactory.Create(Tools.ResolveUri(((ElementEvent)first).BaseUri, String.Empty));
context.BaseUri = baseUri;
if (!context.Handler.HandleBaseUri(baseUri)) ParserHelper.Stop();
}
}
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'RDF'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="element">RDF Element to apply Production to</param>
private void GrammarProductionRDF(RdfXmlParserContext context, ElementEvent element)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTrace("RDF", element);
}
//Check Uri is correct
String localName = element.LocalName;
String prefix = element.Namespace;
if (localName.Equals("RDF") ||
((context.Namespaces.HasNamespace(prefix) && context.Namespaces.GetNamespaceUri(prefix).ToString().Equals(NamespaceMapper.RDF))
|| element.NamespaceAttributes.Any(ns => ns.Prefix.Equals(prefix) && ns.Uri.Equals(NamespaceMapper.RDF))))
{
//This is OK
}
else
{
throw ParserHelper.Error("Unexpected Node '" + element.QName + "', an 'rdf:RDF' node was expected", "RDF", element);
}
//Check has no Attributes
if (element.Attributes.Count > 0)
{
throw ParserHelper.Error("Root Node should not contain any attributes other than XML Namespace Declarations", "RDF", element);
}
//Apply Namespaces
this.ApplyNamespaces(context, element);
//Build a Sublist of all Nodes up to the matching EndElement
IEventQueue<IRdfXmlEvent> subevents = new EventQueue<IRdfXmlEvent>();
IRdfXmlEvent next;
//Make sure we discard the current ElementEvent which will be at the front of the queue
context.Events.Dequeue();
//Gather the Sublist
while (context.Events.Count > 1)
{
subevents.Enqueue(context.Events.Dequeue());
}
//Call the NodeElementList Grammer Production
this.GrammarProductionNodeElementList(context, subevents);
//Next Event in queue should be an EndElementEvent or we Error
next = context.Events.Dequeue();
if (!(next is EndElementEvent))
{
throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', an EndElementEvent was expected", "RDF", element);
}
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'resourcePropertyElt'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="eventlist">Queue of Events that make up the Resource Property Element and its Children</param>
/// <param name="parent">Parent Event (ie. Node) of the Property Element</param>
private void GrammarProductionResourcePropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTracePartial("Resource Property Element");
}
//Cast to an ElementEvent
//We don't validate type here since we know this will be an ElementEvent because the calling function
//will have done this validation previously
IRdfXmlEvent first = eventlist.Dequeue();
IRdfXmlEvent next = eventlist.Peek();
ElementEvent element = (ElementEvent)first;
if (this._traceparsing) this.ProductionTracePartial(element);
//Apply Namespaces
this.ApplyNamespaces(context, element);
//Only allowed one attribute max which must be an ID attribute
String ID = String.Empty;
if (element.Attributes.Count > 1)
{
throw ParserHelper.Error("A Resource Property Element contains too many Attributes, only rdf:ID is permitted", element);
}
else if (element.Attributes.Count == 1)
{
if (!RdfXmlSpecsHelper.IsIDAttribute(element.Attributes.First()))
{
throw ParserHelper.Error("A Resource Property Element was encountered with a single attribute which was not rdf:ID, only rdf:ID is permitted", element);
}
else
{
ID = element.Attributes.First().Value;
}
}
//Next must be an ElementEvent
if (!(next is ElementEvent))
{
throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', expected an ElementEvent as the first Event in a Resource Property Elements Event list", next);
}
//Get list of Sub Events
IEventQueue<IRdfXmlEvent> subevents = new EventQueue<IRdfXmlEvent>();
while (eventlist.Count > 1)
{
subevents.Enqueue(eventlist.Dequeue());
}
this.GrammarProductionNodeElement(context, subevents);
//Check Last is an EndElementEvent
IRdfXmlEvent last = eventlist.Dequeue();
if (!(last is EndElementEvent))
{
throw ParserHelper.Error("Unexpected Event '" + last.GetType().ToString() + "', expected an EndElement Event", last);
}
//Now we can generate the relevant RDF
INode subj, pred, obj;
//Validate the Type of the Parent
if (!(parent is ElementEvent))
{
throw ParserHelper.Error("Unexpected Parent Event '" + parent.GetType().ToString() + "', expected an ElementEvent", parent);
}
ElementEvent parentEl = (ElementEvent)parent;
//Get the Subject Node from the Parent
subj = parentEl.SubjectNode;
//Validate the ID (if any)
if (!ID.Equals(String.Empty))
{
this.ValidateID(context, ID, subj);
}
//Create a Predicate from this Element
pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName);
//Get the Object Node from the Child Node
ElementEvent child = (ElementEvent)next;
obj = child.SubjectNode;
//Assert the Triple
if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop();
//Add Reification where appropriate
if (element.Attributes.Count == 1)
{
//Must be an rdf:ID attribute as we've validated this earlier
//Get the Attribute Event and generate a Uri from it
AttributeEvent attr = element.Attributes.First();
UriReferenceEvent uriref = new UriReferenceEvent("#" + attr.Value, attr.SourceXml);
IUriNode uri = this.Resolve(context, uriref, element.BaseUri);
this.Reify(context, uri, subj, pred, obj);
}
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'propertyElt'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="eventlist">Queue of Events that make up the Property Element and its Children</param>
/// <param name="parent">Parent Event (ie. Node) of the Property Element</param>
private void GrammarProductionPropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTracePartial("Property Element");
}
//Get first thing from the Queue
IRdfXmlEvent first = eventlist.Dequeue();
ElementEvent element;
//Must be an ElementEvent
if (!(first is ElementEvent))
{
//Unexpected Event
throw ParserHelper.Error("Expected an ElementEvent but encountered a '" + first.GetType().ToString() + "'", "PropertyElement", first);
}
//Validate the Uri
element = (ElementEvent)first;
if (this._traceparsing) this.ProductionTracePartial(element);
this.ApplyNamespaces(context, element);
if (!RdfXmlSpecsHelper.IsPropertyElementURI(element.QName))
{
//Invalid Uri
throw ParserHelper.Error("A Property Element was encountered with an invalid URI '" + element.QName + "'\nCore Syntax Terms, Old Syntax Terms and rdf:Description cannot be used as Property Element URIs", "PropertyElement", element);
}
//List Expansion
if (element.QName.Equals("rdf:li"))
{
UriReferenceEvent u = this.ListExpand(parent);
element.SetUri(u);
}
//Need to select what to do based on the Type of Property Element
IRdfXmlEvent next = eventlist.Peek();
//This call inserts the first element back at the head of the queue
//Most of the sub-productions here need this
//Would ideally use Stacks instead of Queues but Queues make more sense for most of the Parsing
this.QueueJump(eventlist, first);
if (element.ParseType == RdfXmlParseType.None)
{
//A Resource/Literal Property Element
if (next is ElementEvent)
{
//Resource
this.GrammarProductionResourcePropertyElement(context, eventlist, parent);
}
else if (next is TextEvent)
{
//Literal
this.GrammarProductionLiteralPropertyElement(context, eventlist, parent);
}
else if (next is EndElementEvent)
{
//An Empty Property Element
this.GrammarProductionEmptyPropertyElement(context, element, parent);
}
else
{
//Error
throw ParserHelper.Error("An Element which should be Parsed with the Default Parsing Rules was encountered without a valid subsequent Event - Parser cannot proceed!", "Property Element", element);
}
}
else if (element.ParseType == RdfXmlParseType.Literal)
{
//A rdf:parseType="Literal" Property Element
this.GrammarProductionParseTypeLiteralPropertyElement(context, eventlist, parent);
}
else if (element.ParseType == RdfXmlParseType.Collection)
{
//A rdf:parseType="Collection" Property Element
this.GrammarProductionParseTypeCollectionPropertyElement(context, eventlist, parent);
}
else if (element.ParseType == RdfXmlParseType.Resource)
{
//A rdf:parseType="Resource" Property Element
this.GrammarProductionParseTypeResourcePropertyElement(context, eventlist, parent);
}
else if (next is EndElementEvent)
{
//An Empty Property Element
this.GrammarProductionEmptyPropertyElement(context, element, parent);
}
else
{
//Error
throw ParserHelper.Error("An Element without a known Parse Type was encountered Or the Parser was unable to determine what to do based on the subsequent event - Parser cannot proceed!", "Node Element", element);
}
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'parseTypeResourcePropertyElt'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="eventlist">Queue of Events that make up the Resource Parse Type Property Element and its Children</param>
/// <param name="parent">Parent Event (ie. Node) of the Property Element</param>
private void GrammarProductionParseTypeResourcePropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTracePartial("Parse Type Resource Property Element");
}
//Get the first Event, should be an ElementEvent
//Type checking is done by the Parent Production
IRdfXmlEvent first = eventlist.Dequeue();
ElementEvent element = (ElementEvent)first;
if (this._traceparsing) this.ProductionTracePartial(element);
//Apply Namespaces
this.ApplyNamespaces(context, element);
//Validate Attributes
String ID = String.Empty;
if (element.Attributes.Count > 2)
{
//Can't be more than 2 Attributes, only allowed an optional rdf:ID and a required rdf:parseType
throw ParserHelper.Error("An Property Element with Parse Type 'Resource' was encountered with too many Attributes. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Resource'", "Parse Type Resource Property Element", element);
}
else
{
//Check the attributes that do exist
foreach (AttributeEvent a in element.Attributes)
{
if (RdfXmlSpecsHelper.IsIDAttribute(a))
{
ID = "#" + a.Value;
}
else if (a.QName.Equals("rdf:parseType"))
{
//OK
}
else
{
//Invalid Attribute
throw ParserHelper.Error("Unexpected Attribute '" + a.QName + "' was encountered on a Property Element with Parse Type 'Resource'. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Resource'", "Parse Type Resource Property Element", element);
}
}
}
//Add a Triple about this
INode subj, pred, obj;
//Get the Subject from the Parent
ElementEvent parentEvent = (ElementEvent)parent;
subj = parentEvent.SubjectNode;
//Validate the ID (if any)
if (!ID.Equals(String.Empty))
{
this.ValidateID(context, ID.Substring(1), subj);
}
//Create the Predicate from the Element
pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName);
//Generate a Blank Node ID for the Object
obj = context.Handler.CreateBlankNode();
//Assert
if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop();
//Reify if applicable
if (!ID.Equals(String.Empty))
{
//Resolve the Uri
UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty);
IUriNode uri = this.Resolve(context, uriref,element.BaseUri);
this.Reify(context, uri, subj, pred, obj);
}
//Get the next event in the Queue which should be either an Element Event or a End Element Event
//Validate this
IRdfXmlEvent next = eventlist.Dequeue();
if (next is EndElementEvent)
{
//Content is Empty so nothing else to do
}
else if (next is ElementEvent)
{
//Non-Empty Content so need to build a sequence of new events
IEventQueue<IRdfXmlEvent> subEvents = new EventQueue<IRdfXmlEvent>();
//Create an rdf:Description event as the container
ElementEvent descrip = new ElementEvent("rdf:Description", element.BaseUri, String.Empty);
descrip.Subject = new BlankNodeIDEvent(String.Empty);
descrip.SubjectNode = obj;
subEvents.Enqueue(descrip);
//Add the current element we were looking at
subEvents.Enqueue(next);
//Add rest of events in list (exceot the last)
while (eventlist.Count > 1)
{
subEvents.Enqueue(eventlist.Dequeue());
}
//Terminate with an EndElement Event
subEvents.Enqueue(new EndElementEvent());
//Process with Node Element Production
this.GrammarProductionNodeElement(context, subEvents);
//Get the last thing in the List
next = eventlist.Dequeue();
}
else
{
throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', expected an ElementEvent or EndElementEvent after a Parse Type Resource Property Element!", "Parse Type Resource Property Element", next);
}
//Check for the last thing being an EndElement Event
if (!(next is EndElementEvent))
{
throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', expected an EndElementEvent to terminate a Parse Type Resource Property Element!", "Parse Type Resource Property Element", next);
}
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'parseTypeLiteralPropertyElt'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="eventlist">Queue of Events that make up the Literal Parse Type Property Element and its Children</param>
/// <param name="parent">Parent Event (ie. Node) of the Property Element</param>
private void GrammarProductionParseTypeLiteralPropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTracePartial("Parse Type Literal Property Element");
}
//Get the first Event, should be an ElementEvent
//Type checking is done by the Parent Production
IRdfXmlEvent first = eventlist.Dequeue();
ElementEvent element = (ElementEvent)first;
if (this._traceparsing) this.ProductionTracePartial(element);
//Apply Namespaces
this.ApplyNamespaces(context, element);
//Validate Attributes
String ID = String.Empty;
if (element.Attributes.Count > 2)
{
//Can't be more than 2 Attributes, only allowed an optional rdf:ID and a required rdf:parseType
throw ParserHelper.Error("An Property Element with Parse Type 'Literal' was encountered with too many Attributes. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Literal'", "Parse Type Literal Property Element", element);
}
else
{
//Check the attributes that do exist
foreach (AttributeEvent a in element.Attributes)
{
if (RdfXmlSpecsHelper.IsIDAttribute(a))
{
ID = "#" + a.Value;
}
else if (a.QName.Equals("rdf:parseType"))
{
//OK
}
else
{
//Invalid Attribute
throw ParserHelper.Error("Unexpected Attribute '" + a.QName + "' was encountered on a Property Element with Parse Type 'Literal'. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Literal'", "Parse Type Literal Property Element", element);
}
}
}
//Get the next event in the Queue which should be a TypedLiteralEvent
//Validate this
IRdfXmlEvent lit = eventlist.Dequeue();
if (!(lit is TypedLiteralEvent))
{
throw ParserHelper.Error("Unexpected Event '" + lit.GetType().ToString() + "', expected a TypedLiteralEvent after a Property Element with Parse Type 'Literal'", "Parse Type Literal Property Element", lit);
}
//Get the Subject from the Parent
INode subj, pred, obj;
ElementEvent parentEl = (ElementEvent) parent;
subj = parentEl.SubjectNode;
//Validate the ID (if any)
if (!ID.Equals(String.Empty))
{
this.ValidateID(context, ID.Substring(1), subj);
}
//Create the Predicate from the Element
pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName);
//Create the Object from the Typed Literal
TypedLiteralEvent tlit = (TypedLiteralEvent)lit;
//At the moment we're just going to ensure that we normalize it to Unicode Normal Form C
String xmllit = tlit.Value;
#if !NO_NORM
xmllit = xmllit.Normalize();
#endif
obj = context.Handler.CreateLiteralNode(xmllit, UriFactory.Create(tlit.DataType));
//Assert the Triple
if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop();
//Reify if applicable
if (!ID.Equals(String.Empty))
{
//Resolve the Uri
UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty);
IUriNode uri = this.Resolve(context, uriref,element.BaseUri);
this.Reify(context, uri, subj, pred, obj);
}
//Check for the last thing being an EndElement Event
IRdfXmlEvent next = eventlist.Dequeue();
if (!(next is EndElementEvent))
{
throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', expected an EndElementEvent to terminate a Parse Type Literal Property Element!", "Parse Type Literal Property Element", next);
}
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'doc'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="root">Root Event to start applying Productions from</param>
private void GrammarProductionDoc(RdfXmlParserContext context, RootEvent root)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTrace("Doc");
}
//Call the RDF Production on the first child if it's an rdf:RDF element
//if (root.Children[0].QName.Equals("rdf:RDF") || root.Children[0].QName.Equals(":RDF"))
String localName = root.Children[0].LocalName;
String prefix = root.Children[0].Namespace;
if (localName.Equals("RDF") &&
((context.Namespaces.HasNamespace(prefix) && context.Namespaces.GetNamespaceUri(prefix).ToString().Equals(NamespaceMapper.RDF))
|| root.DocumentElement.NamespaceAttributes.Any(ns => ns.Prefix.Equals(prefix) && ns.Uri.Equals(NamespaceMapper.RDF))))
{
this.GrammarProductionRDF(context, root.Children[0]);
}
else
{
//No rdf:RDF element
//Drop first element from Queue (which will be a RootEvent)
//Skip straight to NodeElementList production
//context.Events.Dequeue();
this.GrammarProductionNodeElementList(context, context.Events);
}
}
/// <summary>
/// Reifies a Triple
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="uriref">Uri Reference for the Reified Triple</param>
/// <param name="subj">Subject of the Triple</param>
/// <param name="pred">Predicate of the Triple</param>
/// <param name="obj">Object of the Triple</param>
private void Reify(RdfXmlParserContext context, IUriNode uriref, INode subj, INode pred, INode obj)
{
if (!context.Handler.HandleTriple(new Triple(uriref, context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfSubject)), subj))) ParserHelper.Stop();
if (!context.Handler.HandleTriple(new Triple(uriref, context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfPredicate)), pred))) ParserHelper.Stop();
if (!context.Handler.HandleTriple(new Triple(uriref, context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfObject)), obj))) ParserHelper.Stop();
if (!context.Handler.HandleTriple(new Triple(uriref, context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfType)), context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfStatement))))) ParserHelper.Stop();
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'emptyPropertyElt'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="element">Element Event for the Empty Property Element</param>
/// <param name="parent">Parent Event (ie. Node) of the Property Element</param>
private void GrammarProductionEmptyPropertyElement(RdfXmlParserContext context, ElementEvent element, IRdfXmlEvent parent)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTrace("Empty Property Element");
}
//Apply Namespaces
this.ApplyNamespaces(context, element);
INode subj, pred, obj;
ElementEvent parentEl;
//Are there any attributes OR Only a rdf:ID attribute?
if (element.Attributes.Count == 0 || (element.Attributes.Count == 1 && RdfXmlSpecsHelper.IsIDAttribute(element.Attributes[0])))
{
//No Attributes/Only rdf:ID
//Get the Subject Node from the Parent
parentEl = (ElementEvent)parent;
subj = parentEl.SubjectNode;
//Create the Predicate from the Element
pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName);
//Create the Object
if (!element.Language.Equals(String.Empty))
{
obj = context.Handler.CreateLiteralNode(String.Empty, element.Language);
}
else
{
obj = context.Handler.CreateLiteralNode(String.Empty);
}
//Make the Assertion
if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop();
//Reifiy if applicable
if (element.Attributes.Count == 1)
{
//Validate the ID
this.ValidateID(context, element.Attributes[0].Value, subj);
//Resolve the Uri
UriReferenceEvent uriref = new UriReferenceEvent("#" + element.Attributes[0].Value, String.Empty);
IUriNode uri = this.Resolve(context, uriref, element.BaseUri);
this.Reify(context, uri, subj, pred, obj);
}
}
else if (element.Attributes.Count > 0 && element.Attributes.Where(a => RdfXmlSpecsHelper.IsDataTypeAttribute(a)).Count() == 1)
{
//Should be processed as a Typed Literal Event instead
EventQueue<IRdfXmlEvent> temp = new EventQueue<IRdfXmlEvent>();
temp.Enqueue(element);
temp.Enqueue(new TextEvent(String.Empty, String.Empty));
temp.Enqueue(new EndElementEvent());
this.GrammarProductionLiteralPropertyElement(context, temp, parent);
return;
}
else
{
//Check through attributes
IRdfXmlEvent res = null;
//Check through attributes to decide the Subject of the Triple(s)
String ID = String.Empty;
int limitedAttributes = 0;
foreach (AttributeEvent a in element.Attributes)
{
if (RdfXmlSpecsHelper.IsResourceAttribute(a))
{
//An rdf:resource attribute so a Uri Reference
res = new UriReferenceEvent(a.Value, a.SourceXml);
limitedAttributes++;
}
else if (RdfXmlSpecsHelper.IsNodeIDAttribute(a))
{
//An rdf:nodeID attribute so a Blank Node
//Validate the Node ID
if (!XmlSpecsHelper.IsName(a.Value))
{
//Invalid nodeID
throw ParserHelper.Error("The value '" + a.Value + "' for rdf:nodeID is not valid, RDF Node IDs can only be valid Names as defined by the W3C XML Specification", "Empty Property Element", a);
}
res = new BlankNodeIDEvent(a.Value, a.SourceXml);
limitedAttributes++;
}
else if (RdfXmlSpecsHelper.IsIDAttribute(a))
{
//Set the ID for later use in reification
ID = "#" + a.Value;
}
//Check we haven't got more than 1 of the Limited Attributes
if (limitedAttributes > 1)
{
throw ParserHelper.Error("A Property Element can only have 1 of the following attributes: rdf:nodeID or rdf:resource", "Empty Property Element", element);
}
}
if (res == null)
{
//No relevant attributes so an anonymous Blank Node
res = new BlankNodeIDEvent(String.Empty);
}
//Now create the actual Subject Node
if (res is UriReferenceEvent)
{
//Resolve the Uri Reference
UriReferenceEvent uriref = (UriReferenceEvent)res;
subj = this.Resolve(context, uriref, element.BaseUri);
}
else if (res is BlankNodeIDEvent)
{
BlankNodeIDEvent blank = (BlankNodeIDEvent)res;
if (blank.Identifier.Equals(String.Empty))
{
//Have the Graph generate a Blank Node ID
subj = context.Handler.CreateBlankNode();
}
else
{
//Use the supplied Blank Node ID
subj = context.Handler.CreateBlankNode(blank.Identifier);
}
}
else
{
//Should never hit this case but required to get the Code to Compile
//Have the Graph generate a Blank Node ID
subj = context.Handler.CreateBlankNode();
}
//Validate the ID (if any)
if (!ID.Equals(String.Empty))
{
this.ValidateID(context, ID.Substring(1), subj);
}
//Relate the Property element to its parent
parentEl = (ElementEvent)parent;
pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName);
if (!context.Handler.HandleTriple(new Triple(parentEl.SubjectNode, pred, subj))) ParserHelper.Stop();
//Reify if applicable
if (!ID.Equals(String.Empty))
{
//Resolve the Uri
UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty);
IUriNode uri = this.Resolve(context, uriref, element.BaseUri);
this.Reify(context, uri, parentEl.SubjectNode, pred, subj);
}
//Process the rest of the Attributes
foreach (AttributeEvent a in element.Attributes)
{
if (a.QName.Equals("rdf:type"))
{
//A Property Attribute giving a Type
//Assert a Type Triple
UriReferenceEvent type = new UriReferenceEvent(a.Value, a.SourceXml);
pred = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfType));
obj = this.Resolve(context, type, element.BaseUri);
if (!context.Handler.HandleTriple(new Triple(parentEl.SubjectNode, pred, obj))) ParserHelper.Stop();
}
else if (RdfXmlSpecsHelper.IsPropertyAttribute(a))
{
//A Property Attribute
//Validate the Normalization of the Attribute Value
#if !NO_NORM
if (!a.Value.IsNormalized())
{
throw ParserHelper.Error("Encountered a Property Attribute '" + a.QName + "' whose value was not correctly normalized in Unicode Normal Form C", "Empty Property Element", a);
}
else
{
#endif
//Create the Predicate from the Attribute QName
pred = context.Handler.CreateUriNode(UriFactory.Create(Tools.ResolveQName(a.QName, context.Namespaces, context.BaseUri)));
//Create the Object from the Attribute Value
if (element.Language.Equals(String.Empty))
{
obj = context.Handler.CreateLiteralNode(a.Value);
}
else
{
obj = context.Handler.CreateLiteralNode(a.Value, element.Language);
}
//Assert the Property Triple
if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop();
#if !NO_NORM
}
#endif
}
else if (RdfXmlSpecsHelper.IsIDAttribute(a) || RdfXmlSpecsHelper.IsNodeIDAttribute(a) || RdfXmlSpecsHelper.IsResourceAttribute(a))
{
//These have already been processed
//We test for them so that we can then throw ParserHelper.Errors in the final case for unexpected attributes
}
else
{
//Unexpected Attribute
throw ParserHelper.Error("Unexpected Attribute '" + a.QName + "' encountered on a Property Element! Only rdf:ID, rdf:resource, rdf:nodeID and Property Attributes are permitted on Property Elements", "Empty Property Element", element);
}
}
}
}
/// <summary>
/// Resolves a Uri Reference into a Uri Node against a given Base Uri
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="uriref">Uri Reference to Resolve</param>
/// <param name="baseUri">Base Uri to Resolve against</param>
/// <returns></returns>
private IUriNode Resolve(RdfXmlParserContext context, UriReferenceEvent uriref, String baseUri)
{
try
{
if (baseUri.Equals(String.Empty)) baseUri = context.BaseUri.ToSafeString();
IUriNode u = context.Handler.CreateUriNode(UriFactory.Create(Tools.ResolveUri(uriref.Identifier, baseUri)));
return u;
}
catch (Exception ex)
{
//Catch the error so we can wrap in in our own error function
//If it fails then we know we got an error caused by this Event
throw ParserHelper.Error(ex.Message, uriref);
}
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'nodeElement'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="eventlist">Queue of Events that make up the Node Element and its Children to apply the Production to</param>
private void GrammarProductionNodeElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTracePartial("Node Element");
}
//Get First Event in the Queue
IRdfXmlEvent first = eventlist.Dequeue();
//Check it's an ElementEvent
if (!(first is ElementEvent))
{
//Unexpected Event
throw ParserHelper.Error("Expected an ElementEvent but encountered a '" + first.GetType().ToString() + "'", "Node Element", first);
}
//Check it has a valid Uri
ElementEvent element = (ElementEvent)first;
if (this._traceparsing) this.ProductionTracePartial(element);
this.ApplyNamespaces(context, element);
if (!RdfXmlSpecsHelper.IsNodeElementUri(element.QName))
{
throw ParserHelper.Error("A Node Element was encountered with an invalid URI '" + element.QName + "' \nCore Syntax Terms, Old Syntax Terms and rdf:li cannot be used as Node Element URIs", "Node Element", element);
}
//Check the set of Attributes is Valid
int limitedAttributesFound = 0;
String ID = String.Empty;
foreach (AttributeEvent attr in element.Attributes)
{
if (RdfXmlSpecsHelper.IsIDAttribute(attr))
{
ID = attr.Value;
limitedAttributesFound++;
//Set the Subject
element.Subject = new UriReferenceEvent("#" + attr.Value, attr.SourceXml);
}
else if (RdfXmlSpecsHelper.IsNodeIDAttribute(attr))
{
limitedAttributesFound++;
//Validate the Node ID
if (!XmlSpecsHelper.IsName(attr.Value))
{
throw ParserHelper.Error("The value '" + attr.Value + "' for rdf:nodeID is not valid, RDF Node IDs can only be valid Names as defined by the W3C XML Specification", "Node Element", attr);
}
//Set the Subject
element.Subject = new BlankNodeIDEvent(attr.Value, attr.SourceXml);
}
else if (RdfXmlSpecsHelper.IsAboutAttribute(attr))
{
limitedAttributesFound++;
//Set the Subject
element.Subject = new UriReferenceEvent(attr.Value, attr.SourceXml);
}
else if (RdfXmlSpecsHelper.IsPropertyAttribute(attr))
{
//Don't need to do anything here yet
}
else
{
//Unknown and Unexpected Attribute Type
throw ParserHelper.Error("Unexpected Attribute '" + attr.QName + "' was encountered!", "Node Element", element);
}
//Can't have more than 1 of ID, Node ID or About Attributes
if (limitedAttributesFound > 1)
{
throw ParserHelper.Error("A Node Element can only have 1 of the following attributes: rdf:id, rdf:nodeID, rdf:about", "Node Element", element);
}
}
//Generate a Blank Node ID if our Subject is empty
if (element.Subject == null)
{
element.Subject = new BlankNodeIDEvent(element.SourceXml);
}
//Add statements as necessary
INode subj, pred, obj;
if (element.SubjectNode == null)
{
//Don't always want to drop in here since the SubjectNode may already be set elsewhere
if (element.Subject is UriReferenceEvent)
{
UriReferenceEvent uri = (UriReferenceEvent)element.Subject;
subj = this.Resolve(context, uri, element.BaseUri);
}
else if (element.Subject is BlankNodeIDEvent)
{
BlankNodeIDEvent blank = (BlankNodeIDEvent)element.Subject;
//Select whether we need to generate an ID or if there's one given for the Blank Node
//Note that we let the Graph class handle generation of IDs
if (blank.Identifier.Equals(String.Empty))
{
subj = context.Handler.CreateBlankNode();
}
else
{
subj = context.Handler.CreateBlankNode(blank.Identifier);
}
}
else
{
throw ParserHelper.Error("Unexpected Subject generated for a Triple", "Node Element", element.Subject);
}
} else {
subj = element.SubjectNode;
}
//Set the Subject Node property of the Event for later reuse
element.SubjectNode = subj;
//Validate the ID (if any)
if (!ID.Equals(String.Empty))
{
this.ValidateID(context, ID, subj);
}
if (!element.QName.Equals("rdf:Description") && !element.QName.Equals(":Description"))
{
//Assert a Triple regarding Type
pred = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfType));
obj = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName);
if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop();
}
//Go back over Attributes looking for property attributes
foreach (AttributeEvent attr in element.Attributes)
{
if (RdfXmlSpecsHelper.IsPropertyAttribute(attr))
{
if (attr.QName.Equals("rdf:type"))
{
//Generate a Type Triple
pred = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfType));
//Resolve URIRef into a Uri Node
UriReferenceEvent uriref = new UriReferenceEvent(attr.Value, attr.SourceXml);
obj = this.Resolve(context, uriref, element.BaseUri);
if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop();
}
else
{
//Generate a Property Triple
pred = context.Handler.CreateUriNode(UriFactory.Create(Tools.ResolveQName(attr.QName, context.Namespaces, context.BaseUri)));
//Add Language to Literal if necessary
if (element.Language.Equals(String.Empty))
{
obj = context.Handler.CreateLiteralNode(attr.Value);
}
else
{
obj = context.Handler.CreateLiteralNode(attr.Value, element.Language);
}
if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop();
}
}
}
//Handle Child Elements
IEventQueue<IRdfXmlEvent> children = new EventQueue<IRdfXmlEvent>();
while (eventlist.Count > 1)
{
children.Enqueue(eventlist.Dequeue());
}
if (children.Count > 0) this.GrammarProductionPropertyElementList(context, children, element);
//Check Last Event in queue is an EndElement event
IRdfXmlEvent last = eventlist.Dequeue();
if (!(last is EndElementEvent))
{
throw ParserHelper.Error("Unexpected Event '" + last.GetType().ToString() + "', expected an EndElement Event", "NodeElement", last);
}
}
private IUriNode Resolve(RdfXmlParserContext context, ElementEvent el)
{
try
{
IUriNode u = context.Handler.CreateUriNode(UriFactory.Create(Tools.ResolveQName(el.QName, context.Namespaces, context.BaseUri)));
return u;
}
catch (Exception ex)
{
throw ParserHelper.Error(ex.Message, el);
}
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'parseTypeCollectionPropertyElt'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="eventlist">Queue of Events that make up the Collection Parse Type Property Element and its Children</param>
/// <param name="parent">Parent Event (ie. Node) of the Property Element</param>
private void GrammarProductionParseTypeCollectionPropertyElement(RdfXmlParserContext context, IEventQueue<IRdfXmlEvent> eventlist, IRdfXmlEvent parent)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTracePartial("Parse Type Collection Property Element");
}
//Get the first Event, should be an ElementEvent
//Type checking is done by the Parent Production
IRdfXmlEvent first = eventlist.Dequeue();
ElementEvent element = (ElementEvent)first;
if (this._traceparsing) this.ProductionTracePartial(element);
//Apply Namespaces
this.ApplyNamespaces(context, element);
//Validate Attributes
String ID = String.Empty;
if (element.Attributes.Count > 2)
{
//Can't be more than 2 Attributes, only allowed an optional rdf:ID and a required rdf:parseType
throw ParserHelper.Error("An Property Element with Parse Type 'Collection' was encountered with too many Attributes. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Collection'", "Parse Type Collection Property Element", element);
}
else
{
//Check the attributes that do exist
foreach (AttributeEvent a in element.Attributes)
{
if (RdfXmlSpecsHelper.IsIDAttribute(a))
{
ID = "#" + a.Value;
}
else if (a.QName.Equals("rdf:parseType"))
{
//OK
}
else
{
//Invalid Attribute
throw ParserHelper.Error("Unexpected Attribute '" + a.QName + "' was encountered on a Property Element with Parse Type 'Collection'. Only rdf:ID and rdf:parseType are allowed on Property Elements with Parse Type 'Collection'", "Parse Type Collection Property Element", element);
}
}
}
//Build sequence of Blank Nodes
IRdfXmlEvent next;
IRdfXmlEvent nodeElement;
Queue<ElementEvent> seqNodes = new Queue<ElementEvent>();
while (eventlist.Count > 1)
{
#region Node Element Processing
//Need to process the Node Element first
//Create a new Sublist
IEventQueue<IRdfXmlEvent> subevents = new EventQueue<IRdfXmlEvent>();
int nesting = 0;
nodeElement = eventlist.Peek();
//Add Node Element to sequence
seqNodes.Enqueue((ElementEvent)nodeElement);
//Gather the Sublist taking account of nesting
do
{
next = eventlist.Dequeue();
subevents.Enqueue(next);
if (next is ElementEvent)
{
nesting++;
}
else if (next is EndElementEvent)
{
nesting--;
}
} while (nesting > 0);
//Call the next Grammar Production
this.GrammarProductionNodeElement(context, subevents);
#endregion
}
//Build a triple expressing the start of the list (which may be an empty list)
INode subj, pred, obj;
INode firstPred, restPred;
INode b1, b2;
//Subject comes from Parent
ElementEvent parentElement = (ElementEvent)parent;
subj = parentElement.SubjectNode;
//Validate the ID (if any)
if (!ID.Equals(String.Empty))
{
this.ValidateID(context, ID.Substring(1), subj);
}
//Predicate from the Element
pred = this.Resolve(context, element);//context.Handler.CreateUriNode(element.QName);
if (seqNodes.Count > 0)
{
//Non-empty list
ElementEvent node;
//Get first Element from the Queue
node = seqNodes.Dequeue();
//Object is first thing in the Sequence which we create a Blank Node for
b1 = context.Handler.CreateBlankNode();
//Assert
if (!context.Handler.HandleTriple(new Triple(subj, pred, b1))) ParserHelper.Stop();
//Reify if applicable
if (!ID.Equals(String.Empty))
{
//Resolve the Uri
UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty);
IUriNode uri = this.Resolve(context, uriref, element.BaseUri);
this.Reify(context, uri, subj, pred, b1);
}
//Set the first element in the list
subj = b1;
firstPred = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfListFirst));
if (!context.Handler.HandleTriple(new Triple(subj, firstPred, node.SubjectNode))) ParserHelper.Stop();
//Middle elements of the list
restPred = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfListRest));
while (seqNodes.Count >= 1)
{
node = seqNodes.Dequeue();
//Set Node 2 to be the rest of the previous items list
b2 = context.Handler.CreateBlankNode();
if (!context.Handler.HandleTriple(new Triple(b1, restPred, b2))) ParserHelper.Stop();
//Set Node 2 to be the start of it's own list
if (!context.Handler.HandleTriple(new Triple(b2, firstPred, node.SubjectNode))) ParserHelper.Stop();
b1 = b2;
}
//Set last element of the list to have its rest as nil
if (!context.Handler.HandleTriple(new Triple(b1, restPred, context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfListNil))))) ParserHelper.Stop();
}
else
{
//Empty list
//Object is therefore rdf:nil
obj = context.Handler.CreateUriNode(UriFactory.Create(RdfSpecsHelper.RdfListNil));
//Assert
if (!context.Handler.HandleTriple(new Triple(subj, pred, obj))) ParserHelper.Stop();
//Reify if applicable
if (!ID.Equals(String.Empty))
{
//Resolve the Uri
UriReferenceEvent uriref = new UriReferenceEvent(ID, String.Empty);
IUriNode uri = this.Resolve(context, uriref, element.BaseUri);
this.Reify(context, uri, subj, pred, obj);
}
}
//Check last event is an EndElementEvent
next = eventlist.Dequeue();
if (!(next is EndElementEvent))
{
throw ParserHelper.Error("Unexpected Event '" + next.GetType().ToString() + "', expected an EndElementEvent to terminate a Parse Type Collection Property Element!", "Parse Type Collection Property Element", next);
}
}
/// <summary>
/// Validates that an ID is correctly formed and has only been used once in the context of a given Subject
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="id">ID to Validate</param>
/// <param name="subj">Subject that the ID pertains to</param>
private void ValidateID(RdfXmlParserContext context, String id, INode subj)
{
//Validate the actual ID value
if (!XmlSpecsHelper.IsName(id))
{
throw new RdfParseException("The value '" + id + "' for rdf:ID is not valid, RDF IDs can only be valid Names as defined by the W3C XML Specification");
}
//Validate that the ID hasn't been used more than once in the same Base Uri context
if (context.IDs.ContainsKey(id))
{
if (context.IDs[id].Contains(subj))
{
throw new RdfParseException("An rdf:ID must be unique to a Node within a File, the rdf:ID '" + id + "' has already been used for a Node in this RDF/XML File!");
}
else
{
context.IDs[id].Add(subj);
}
}
else
{
context.IDs.Add(id, new List<INode>() { subj });
}
}
/// <summary>
/// Given an XML Node creates the relevant RDF/XML Events for it and recurses as necessary
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="node">The Node to create Event(s) from</param>
/// <param name="parent">The Parent Node of the given Node</param>
/// <returns></returns>
private ElementEvent GenerateEvents(RdfXmlParserContext context, XmlNode node, IRdfXmlEvent parent)
{
//Get the Base Uri
String baseUri = String.Empty;
if (parent is ElementEvent)
{
baseUri = ((ElementEvent)parent).BaseUri;
}
//Create an ElementEvent for the Node
ElementEvent element = new ElementEvent(node.LocalName, node.Prefix, baseUri, node.OuterXml);
//Set the initial Language from the Parent
ElementEvent parentEl = (ElementEvent)parent;
element.Language = parentEl.Language;
#region Attribute Processing
//Iterate over Attributes
bool parseTypeLiteral = false;
foreach (XmlAttribute attr in node.Attributes)
{
//Watch out for special attributes
if (attr.Name == "xml:lang")
{
//Set Language
element.Language = attr.Value;
}
else if (attr.Name == "xml:base")
{
//Set Base Uri
if (RdfXmlSpecsHelper.IsAbsoluteURI(attr.Value))
{
//Absolute Uri
element.BaseUri = attr.Value;
}
else if (!element.BaseUri.Equals(String.Empty))
{
//Relative Uri with a Base Uri to resolve against
//element.BaseUri += attr.Value;
element.BaseUri = Tools.ResolveUri(attr.Value, element.BaseUri);
}
else
{
//Relative Uri with no Base Uri
throw new RdfParseException("Cannot resolve a Relative Base URI since there is no in-scope Base URI");
}
}
else if (attr.Prefix == "xmlns")
{
//Register a Namespace
String uri;
if (attr.Value.StartsWith("http://"))
{
//Absolute Uri
uri = attr.Value;
}
else if (!element.BaseUri.Equals(String.Empty))
{
//Relative Uri with a Base Uri to resolve against
//uri = element.BaseUri + attr.Value;
uri = Tools.ResolveUri(attr.Value, element.BaseUri);
}
else
{
//Relative Uri with no Base Uri
throw new RdfParseException("Cannot resolve a Relative Namespace URI since there is no in-scope Base URI");
}
NamespaceAttributeEvent ns = new NamespaceAttributeEvent(attr.LocalName, uri, attr.OuterXml);
element.NamespaceAttributes.Add(ns);
}
else if (attr.Prefix == String.Empty && attr.Name == "xmlns")
{
//Register a Default Namespace (Empty Prefix)
String uri;
if (attr.Value.StartsWith("http://"))
{
//Absolute Uri
uri = attr.Value;
}
else if (!element.BaseUri.Equals(String.Empty))
{
//Relative Uri with a Base Uri to resolve against
//uri = element.BaseUri + attr.Value;
uri = Tools.ResolveUri(attr.Value, element.BaseUri);
}
else
{
//Relative Uri with no Base Uri
throw new RdfParseException("Cannot resolve a Relative Namespace URI since there is no in-scope Base URI");
}
NamespaceAttributeEvent ns = new NamespaceAttributeEvent(String.Empty, uri, attr.OuterXml);
element.NamespaceAttributes.Add(ns);
}
else if (attr.Prefix == "xml" || (attr.Prefix == String.Empty && attr.LocalName.StartsWith("xml")))
{
//Ignore other Reserved XML Names
}
else if (attr.Name == "rdf:parseType" && attr.Value == "Literal")
{
//Literal Parse Type
parseTypeLiteral = true;
//Create the Attribute
AttributeEvent attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, attr.Value, attr.OuterXml);
element.Attributes.Add(attrEvent);
//Set ParseType property correctly
element.ParseType = RdfXmlParseType.Literal;
}
else if (attr.Name == "rdf:parseType")
{
//Some other Parse Type
//Create the Attribute
AttributeEvent attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, attr.Value, attr.OuterXml);
element.Attributes.Add(attrEvent);
//Set the ParseType property correctly
if (attr.Value == "Resource")
{
element.ParseType = RdfXmlParseType.Resource;
}
else if (attr.Value == "Collection")
{
element.ParseType = RdfXmlParseType.Collection;
}
else
{
//Have to assume Literal
element.ParseType = RdfXmlParseType.Literal;
parseTypeLiteral = true;
//Replace the Parse Type attribute with one saying it is Literal
element.Attributes.Remove(attrEvent);
attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, "Literal", attr.OuterXml);
}
}
else
{
//Normal Attribute which we generate an Event from
AttributeEvent attrEvent = new AttributeEvent(attr.LocalName, attr.Prefix, attr.Value, attr.OuterXml);
element.Attributes.Add(attrEvent);
}
}
//Validate generated Attributes for Namespace Confusion and URIRef encoding
foreach (AttributeEvent a in element.Attributes)
{
//Namespace Confusion should only apply to Attributes without a Namespace specified
if (a.Namespace.Equals(String.Empty))
{
if (RdfXmlSpecsHelper.IsAmbigiousAttributeName(a.LocalName))
{
//Can't use any of the RDF terms that mandate the rdf: prefix without it
throw ParserHelper.Error("An Attribute with an ambigious name '" + a.LocalName + "' was encountered. The following attribute names MUST have the rdf: prefix - about, aboutEach, ID, bagID, type, resource, parseType", element);
}
}
//URIRef encoding check
if (!RdfXmlSpecsHelper.IsValidUriRefEncoding(a.Value))
{
throw ParserHelper.Error("An Attribute with an incorrectly encoded URIRef was encountered, URIRef's must be encoded in Unicode Normal Form C", a);
}
}
#endregion
//Don't proceed if Literal Parse Type is on
if (parseTypeLiteral)
{
//Generate an XMLLiteral from its Inner Xml (if any)
TypedLiteralEvent lit = new TypedLiteralEvent(node.InnerXml.Normalize(), RdfSpecsHelper.RdfXmlLiteral, node.InnerXml);
element.Children.Add(lit);
return element;
}
//Are there Child Nodes?
if (node.HasChildNodes)
{
//Take different actions depending on the Number and Type of Child Nodes
if (node.ChildNodes.Count > 1)
{
//Multiple Child Nodes
//Iterate over Child Nodes
foreach (XmlNode child in node.ChildNodes)
{
//Ignore Irrelevant Node Types
if (this.IsIgnorableNode(child))
{
continue;
}
//Generate an Event for the Child Node
ElementEvent childEvent = this.GenerateEvents(context, child, element);
element.Children.Add(childEvent);
}
}
else if (node.ChildNodes[0].NodeType == XmlNodeType.Text)
{
//Single Child which is a Text Node
//Generate a Text Event
TextEvent text = new TextEvent(node.InnerText.Normalize(), node.OuterXml);
element.Children.Add(text);
}
else if (node.ChildNodes[0].NodeType == XmlNodeType.CDATA)
{
//Single Child which is a CData Node
TextEvent text = new TextEvent(node.InnerXml.Normalize(), node.OuterXml);
element.Children.Add(text);
}
else
{
//Single Child which is not a Text Node
//Recurse on the single Child Node
if (!this.IsIgnorableNode(node.ChildNodes[0]))
{
ElementEvent childEvent = this.GenerateEvents(context, node.ChildNodes[0], element);
element.Children.Add(childEvent);
}
}
}
return element;
}
/// <summary>
/// Reads RDF/XML from the given XML Document
/// </summary>
/// <param name="g">Graph to load into</param>
/// <param name="document">XML Document</param>
public void Load(IGraph g, XmlDocument document)
{
if (g == null) throw new RdfParseException("Cannot read RDF into a null Graph");
if (document == null) throw new RdfParseException("Cannot read RDF from a null XML Document");
try
{
//Create a new Parser Context and Parse
RdfXmlParserContext context = new RdfXmlParserContext(g, document, this._traceparsing);
this.Parse(context);
}
catch (XmlException xmlEx)
{
//Wrap in a RDF Parse Exception
throw new RdfParseException("Unable to Parse this RDF/XML since System.Xml was unable to parse the document into a DOM Tree", xmlEx);
}
catch (IOException ioEx)
{
//Wrap in a RDF Parse Exception
throw new RdfParseException("Unable to Parse this RDF/XML due to an IO Exception", ioEx);
}
catch (Exception)
{
//Throw unexpected errors upwards as-is
throw;
}
}
/// <summary>
/// Gets all events from the XML DOM
/// </summary>
/// <param name="context">Parser Context</param>
public void GetAllEvents(RdfXmlParserContext context)
{
RootEvent root;
XmlNodeList nodes = this._document.GetElementsByTagName("rdf:RDF");
if (nodes.Count == 0)
{
//Not using rdf:RDF
root = this.GenerateEventTree(context, this._document.DocumentElement);
}
else if (nodes.Count > 1)
{
throw new RdfParseException("XML contains multiple rdf:RDF Nodes and is therefore not a valid RDF/XML Document");
}
else
{
//Must thus be only 1 rdf:RDF element
root = this.GenerateEventTree(context, nodes[0]);
}
this.FlattenEventTree(context, root, 0);
}
/// <summary>
/// Implementation of the RDF/XML Grammar Production 'doc'
/// </summary>
/// <param name="context">Parser Context</param>
/// <param name="root">Root Event to start applying Productions from</param>
private void GrammarProductionDoc(RdfXmlParserContext context, RootEvent root)
{
//Tracing
if (this._traceparsing)
{
this.ProductionTrace("Doc");
}
//Call the RDF Production on the first child if it's an rdf:RDF element
if (root.Children[0].QName.Equals("rdf:RDF") || root.Children[0].QName.Equals(":RDF"))
{
this.GrammarProductionRDF(context, root.Children[0]);
}
else
{
//No rdf:RDF element
//Drop first element from Queue (which will be a RootEvent)
//Skip straight to NodeElementList production
//context.Events.Dequeue();
this.GrammarProductionNodeElementList(context, context.Events);
}
}
